Trucks controlled by a steering arm normally are designed for a walking operation or a rider operation, respectively. For the latter case the trucks have a platform for the operator. Standing on the platform, he seizes a steering head connected to a steering rod. Trucks designed for a riding operation in most cases have a relatively short steering arm, in any case shorter than those for mere walking operation. However, it is also known to use rider trucks for the walking operation. In this case, the platform is arranged at the rear side of the truck. The operator may stand on the platform and grasps the steering head with one hand for actuation purposes while the other hand grasps a retaining bail which extends above the housing of the truck. Such a truck is known from the U.S. patents U.S. Pat. No. 6,464,025, U.S. Pat. No. 5,245,144, U.S. Pat. No. 5,964,313 or U.S. Pat. No. 6,382,359. The steering arm includes a steering rod which can be pivoted about a horizontal axis, and concurrently is supported for rotation about a vertical axis in order to effect a steering motion on the wheel to be steered. A steering head is attached to the upper end of the steering rod which typically is symmetrical to the longitudinal axis of the steering rod. The steering head includes a transverse portion or support portion which extends transverse to the steering rod. A horn extends centrally from the transverse portion to the rear. Rod-shaped grip portions are located on both sides of the horn which are spaced to a transverse portion and extend proximately parallel to the transverse portion. The grip portions are supported for rotation about their longitudinal axis. The rotational bearing of the grip portion takes place at their inner end at the horn and at the outer end at leg portions which approximately extend parallel to the horn and are connected to the transverse portion. Such a structure of a steering head is not only known from the above mentioned publications, rather is known from steering arms of similar trucks. The rotation of the grip portions have the function to actuate the driving motor or the control circuit thereof, respectively. The driving speed corresponds to the rotational angle of the grip portions. The grip portions either are mechanically or electrically coupled, so that it makes no difference which of the grip portions is actuated.
The described trucks also need a driving means for the raising and lowering of a load bearing means which normally is a load carrying fork. The control of the load bearing means also takes place at the steering head. In the above mentioned publications the upper side of a steering head has a key-element arrangement for the actuation of the drive means for lowering or raising of the load bearing means. From EP 1 153 815 A1 a steering head has become known wherein grip portions are rigid, and a rotary driving switch is located between the horn and the adjacent ends of the grip portions. From U.S. Pat. No. 5,595,259 it has become known to provide the grip portions to actuate a driving switch and to provide extensions (paddle) at the ends thereof, whereby the rotational actuation during walking operation is to be facilitated. From DE 4 413 631 A1 it is known to provide keys or push-buttons between the horn and the grip portions to effect the raising and lowering of the load bearing means.
It is an object of the invention to provide a steering arm for the walkie/rider trucks wherein independent of the angular position of the steering arm and independent of whether the operator rides or walks an ergonomic favourable actuation of the driving motor and the drive for the raising and lowering operation can be achieved.